ANSWER
The correct answer is option B
EXPLANATION
When we analyse carefully we can see that PQR is mapped on to P'Q'R' by the rule
[tex](x,y)\rightarrow (-x,y)[/tex]
[tex]P(1,4)\rightarrow P'(-1,4)[/tex]
[tex]Q(2,2)\rightarrow Q'(-2,2)[/tex]
[tex]R(-2,1)\rightarrow R'(2,2)[/tex]
That is to say the x-coordinates are negated. Hence y-axis is the mirror line.
Since reflection is a rigid motion, the two triangles are congruent. That means the two triangles PQR and P'Q'R' are equal in all respect.
See graph in attachment.